A well-structured roof protects a building from external elements. This is because the added six layers underlying the visible top ensure the durability and strength of the structure against water infiltration and extreme weather conditions. The roof system begins with the decking for structural support, followed by underlayment for moisture barrier, ended with the final roof covering against harsh climate. Insulation and ventilation layers are also incorporated, or some additional layers are added as per the local conditions. 

6 Layers of Roof That Maximize Your Roof’s Strength

Visibly, the roof is just a structure for an ordinary person that covers the house from the top. However, it is a complex system made up of multiple layers that work together to shield your home from the various elements. Each layer serves a different purpose and creates a robust structure.

Roof Deck — Foundational Layer of the Entire System 

The roof deck provides essential support and stability. It is a fundamental component upon which other roofing materials are installed. Therefore, the deck is specifically designed to bear the weight of the roof and everything it supports for the overall integrity of the building. 

Materials Used

• Plywood decks are laminated layers of wood veneer. They are popular due to their strength and versatility.
• Oriented Strand Board is made by compressing wood strands and is considered affordable in modern construction. 
• Concrete decks are suitable for flat roofs but can be heavier and expensive to install.
• Metal decking is lightweight and strong enough to work in the UK’s harsh weather conditions.

Underlayment — Critical Water-Proof Barrier 

The underlayment is installed directly over the roof deck and beneath the primary roofing materials. It functions as a secondary layer of defence against moisture and water penetration into the inside structure. Moreover, in case of roof covering failure, the underlayment provides a backup barrier to water reaching the roof deck and causing leaks.

Materials Used

• Felt underlayment is made from an organic or fibreglass base saturated with asphalt. It is available in different weights and offers various levels of durability. 
• The synthetic option is manufactured from polypropylene or polyethene. It is generally lightweight, non-skid and more resistant to tearing and moisture absorption.
• Underlayment made of rubberized asphalt membrane, often with a self-adhering feature. This is excellent for UK areas prone to heavy rains and ice dams, as it forms a tight seal around fasteners. 

Insulation — Layer to Make Building Energy-Efficient

The insulating layer in a roof is specially installed in UK homes for thermal comfort and energy efficiency. It helps maintain consistent indoor temperatures and reduces energy costs associated with heating and cooling by up to 40% to 50%. Adequate insulation creates a more comfortable living environment by regulating temperature according to the outer climate. This thermal resistance is measured by the R-value, which indicates the effectiveness of insulation in resisting heat flow.

Materials Used

• Fibreglass insulation in batts or loose-fill form is cost-effective and widely used in the UK. 
• Made from polyurethane, spray foam insulation is applied as a liquid that expands and hardens to create a solid layer. 
• Another durable option is rigid foam board, which can be installed above or below the deck. This is mainly composed of polystyrene, polyiso, or polyurethane for high insulation values.

Ventilation Layer — Extends The Roof Lifespan

There are two primary types of roof ventilation systems: active and passive. Active ventilation uses electrically powered systems to enhance air movement, while passive ventilation relies on natural air current and thermal dynamics. These layers are necessary for effective air circulation indoors and reduce heat buildup. Without ventilation, roofs are susceptible to mold growth and premature deterioration. 

Material and Types Used

• Located in the eaves, steel or aluminium-made soffit vents allow intake air to enter the attic, which is crucial for maintaining continuous air circulation. 
• Ridge vents, installed at the peak, serve as an exhaust that enables warm or humid air to escape the attic. They are designed to run the entire length of the ridge and are available in a variety of materials. 

Flashing — Seal Loose Areas to Prevent Water Protrusion

Roof flashing is a thin metal sheet installed around intersections, such as chimneys and vents. It directs water away from these critical areas and prevents leaks. The effectiveness of flashing greatly contributes to the overall durability and longevity of the roof. Commonly, it can be installed in two forms in the UK; step or continuous.

Materials Used

• The most widely used galvanized steel coated with zinc is suitable for resisting rust and corrosion.
• Aluminium flashing is another preferable option by Norwich Contractors due to its ease of manipulation and lightweight. 
• Copper, lead, or MBR are also favoured in certain regions for their distinct benefits.

Roofing Material — The Outermost Layer to be Visible

Roofing material serves as the first line of defence against the environmental elements. It is the topmost layer of the roof that is visible from the ground. Different roofing materials and styles can be combined to create a unique visual appeal and complement the overall design of the home. This flexibility allows homeowners to express their preferences while maintaining functionality. 

Materials Used

• In the UK, asphalt shingles are the most common roofing material. They are affordable and come in various styles.
• Slate and tile roofing are highly durable and aesthetically pleasing. It is a natural stone that can withstand rain, fire and insects.
• Made of different metals, such as aluminium, copper, and zinc, roofs resist fire and reflect heat for energy efficiency.

Conclusion:

The layers of a roof work together to ensure the durability of the structure and protection from external elements. From foundational roof decking and efficient insulation to appealing roofing material, each layer serves a specific purpose. Understanding all of this helps you consult Norwich Roofing professionals to make an informed decision.